Improvement in lightning-conductors



UNITED STATES PATENT OEETCE.

ISAAC JOHNSON, ,OF LODI STATION, ILLINOIS.

IMPROVEMENT IN LIGHTNING-CONDUCTORES.

Specicationiforming part of Letters Patent No. 47,3!0, dated April 1 8, 1865.

lmy improved manner; Fig. 2, a longitudinal section of the conductor through the joint of two of the contiguous lengths of which the conductor is composed; Fig. 3, a cross-section of the conductor through one of thejoints.

Like letters designate corresponding parts in all of the gnres.

In the construction and application of lightning-conductors there are several important requisites, of which the most essential are, sufficient conducting capacity, the utmost dispersive capability, continuity of proper shape throughout the entire length, the most surface and least weight consistent with compactness and conducting power, the' necessary strength, rigidity, and durability, cheapness and readiness of construction, portability and convenience in putting up. The best conductor is one which best fulfills all 'of these requisites without effecting either to the detriment of any other. The object of myinvention istoattaiu these advantages to the fullest extent practicable.

For the conductor I employ copper, which is the best practicable material, in sheet form, so as to obtain the required surface, sufficient in size or quantity of metal to secure the full conducting capacity, triangular in form or cross section, whereby the best dispersive power is attained and the greatest rigidity and strength are produced of which sheet metal forming a tube is capable. The sides are aiso made more or less concave or arching inward, so as to render the angles more acute and increase the strength; and to complete the requisite of strength, as well as' to furnish the best means -of uniting the whole together, I extend an iron wire through the entire length, or through such portions as may require it, inside ot the triangular tube.

tion and superior usefulness ot purpose there-l by 1n all respects consistent with one another.

As shown in the drawings, I construct' the tube A of strips of sheet-copper, folded by a suit-able machine or otherwise into a triangu?` lar tube, and the tube may be made of asin' gie thickness of the sheet of copper, going once around, or of two'thicknesses, the second.

folded in succession over the iirst or inner thickness, as shown in Figs. 2 and 3, or cfa greater number, if desire l.

crease the acuteness thereof I bend or arch the sides c c c of the tube inward toward the center, as shown in Fig. 3. This arched or concave form also renders the cavity of the'tubemuch smaller, so thata small wire, O, is passed through it and fills it to the middle of thesides. and although ittits loosely in the tube, so as tol be readily inserted and withdrawn, the inwardly-arched sides, whenever there is a tendency to bend or crush the rod, bear against the wire,

thereby sustaining the shape and securing,

comparatively great strength and rigidity.

This eect is much greater with the triangu lar than with any other possible form, for not only is the effect due to the arching as great as in any other form, but one angle is always in the direction of the strain and resists it by a triangular brace, the strongest possible. A spiral twist is generally given to the tube A, as indicated in the drawings.

The angles a a a of the triangle are1 more acute than those of any other polygonal form, and it is well known that the sharper or more acute the edges of a conductor the greater the power or facility to disperse or dissipate the electricity, and consequently the more effectual to discharge it without injurious effect to the building 5 but there is another principle arising 1 The anglesa a a are mace as sharp as practicable, and to inl 2 saale from andpeculiar to the triangular form of much I value in increasing the dispersive power of the conductor, and, besides, it is believed, increas ing the conducting capacity of therod. This is the greatly-increased effectof induction produced by the triangular form, or, by whatever theory the induction of electricity is explained, wheth er of positive and negative states or quantities of one fluid or of two kinds of electricity, the fact is the same, that whenever there is an excess or tension of electricity in anything or part of anything there is always the opposite electric state produced in neighboring 0r opposite things or parts of the same thing; hence, with the triangular form, since each angle is opposite to the middle of a side, the

fullinductive eiiect is produced without diminishing or neutralizing the tension'at the I other angles of the conductor, whereas, with the 'quadrangular' or any other angular form ofcouductor except the triangular, one angle is always exactly or more nearly opposite 'to another angle, so that one more or less neutralizes the action of the other and a less tension or quantity ofthe electricity is possible. This increased tension in the angles of the triangular form increases the dispersive action of the electricity, and there appears reason to believe that the whole conductor is thereby.ren dered capable of conducting a greater amount of electrici ty, under similar circumstances, than other forms of conductor of equal quantity ofA metal and extent of surface. Then, the trianguiariwardly-arched form, by givingasmaller internal cavity and requiringa smaller redor wire, 0, than the quadrangularor any. other form of agreaternumber of sides, cheapens the construction and facilitates the portability ,of the'condu'ctor in a peculiar manner, for,

usingA onlya simple wire of moderate size gives .suicient strength, by binding the lengths or l sections Vof the tubularxportion A oi the com dnctortogether, which are -snciently rigid in themselves, owing to their triangular form;

This wire is not only cheaper in itself than a rod, but it can be carried about in any length,

. coiled up or wound on a reel, and then it. is.

readily straightened again with the hands in putting up the conductor; whereas' a rod of iron of suicient size to t other angular forms of conductor practically cannot be coiled up,

but must becarriedinlengthsordivisions,

and the joints of rods in sections are-veryiapt to break, which renders the 'rods much inferior to a continuous wire, the latter beingvery seldom liable to break.

The lengths or sections of thecopper tube A are made a little smaller or contracted at the -upper ends, as at g, so as to enter the lowerends of the lengths above an inch or two, and thus couple the sections together. When therod is put up the lengths or sections are i slipped or strung successively upon the wire O, their ends connected by inserting one in another, as above, and then simply indentin g the lapped joints in one or' two places, as indicated at h h, Fig. 2, with pinchers or their equivalent.

Thus all rivets, screws, and soldering are dispensed with and the joints are connected all the more rapidly and with slightexpense. Less obstruction to the currents of electricity is also otteredin this way. The conductors, likewise,

the point B. The triangular is obviously the best angular form which can be given to the point, fnltilling all the requisites of the best quietly-receivingquality. Thetriangular form -of the, conductor A enables the point B to be inserted in or joined to it and have the edges d au of the conductor exactly continuons with .the edges b b b of the point, and the sides/c c c of the conductor continuous withthe sides d d d of the point. This secures another very good result, since it is known that a conductor which has no breaks, bends, nor obstructions in its surface is better and surer to conduct electricity than thosev Ahaving such defects.

The socket-shank of the point B is inserted t into the upper end of the tube A, and may be secured therein by a rivet, f," Fig. 1,*or in any other suitable manner.' The triangular form of the conductor, the

best in itseliand the triangular form of thepoint, .the best in itself, are thus combined in this conductor, and in their union a third feature 'of perfectionis secured-that of the coutinuous angles and sides.- No'ot-her-eonductor, within my knowledge, has ever 'so perfectly combined the best qualities of a safe lightningconductor. f

AHaving` thus fully described -my improved lightningfconduetor, I wishit to bejunder- Y stood that .I do not claim. 4'an angular nor a tubular .conductor in itself, nor arching its] sidesnor extending a red throughA its center,

separatelyconsidered; butsincelshowthatthe triangular form enhances thegood effects ofthe other features, thus'frendering the angles of a" tubular conductor more acute and dispersive,

and the tube stronger and more ri'gichand since the central iron rod is thereby enabled to be much smaller-in fact, a-merewire-thus rendering it cheaper, lighter, and more portable, and in one pieee- What vI claim as my invention, and .desire to secu're'by Letters Patent, is

A lightning-conductor composed of a triam guiar tube, A, with inwardly-arched sides, in

combination with a continuous central' iron wire, C, extending partly or wholly through the length of the tube, substantially as andfor the purposes herein set forth.

The above specification of my improved" lightning conductor signed by me this 20th day' of December, 1864.

Witnesses y J. S. BROWN, S. Wo Woon.

ISAAC JOHNSON. 

